path: root/tests/tui_pow.c

/* Test file for mpfr_ui_pow and mpfr_ui_pow_ui.

Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
Contributed by the Arenaire and Cacao projects, INRIA.

This file is part of the GNU MPFR Library.

The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.

The GNU MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
License for more details.

You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

#include "mpfr-test.h"

static void
test1 (void)
{
  mpfr_t x, y, z, a;
  int res1, res2;

  mpfr_init2 (x, 32);
  mpfr_init2 (y, 65);
  mpfr_init2 (z, 17);
  mpfr_init2 (a, 17);

  mpfr_set_str_binary (x, "-0.101110001001011011011e-9");
  mpfr_ui_pow (y, 7, x, MPFR_RNDN);

  mpfr_set_prec (x, 40);
  mpfr_set_str_binary (x, "-0.1100101100101111011001010010110011110110E-1");
  mpfr_set_prec (y, 74);
  mpfr_ui_pow (y, 8, x, MPFR_RNDN);
  mpfr_set_prec (x, 74);
  mpfr_set_str_binary (x, "0.11100000010100111101000011111011011010011000011000101011010011010101000011E-1");
  if (mpfr_cmp (x, y))
    {
      printf ("Error for input of 40 bits, output of 74 bits\n");
      exit (1);
    }

  /* Check for ui_pow_ui */
  mpfr_ui_pow_ui (x, 0, 1, MPFR_RNDN);
  MPFR_ASSERTN(mpfr_cmp_ui (x, 0) == 0 && MPFR_IS_POS (x));
  mpfr_ui_pow_ui (x, 0, 4, MPFR_RNDN);
  MPFR_ASSERTN(mpfr_cmp_ui (x, 0) == 0 && MPFR_IS_POS (x));
  res1 = mpfr_ui_pow_ui (z, 17, 42, MPFR_RNDD);
  mpfr_set_ui (x, 17, MPFR_RNDN);
  mpfr_set_ui (y, 42, MPFR_RNDN);
  res2 = mpfr_pow (a, x, y, MPFR_RNDD);
  if (mpfr_cmp (z, a) || res1 != res2)
    {
      printf ("Error for ui_pow_ui for 17^42\n"
              "Inexact1 = %d Inexact2 = %d\n", res1, res2);
      mpfr_dump (z);
      mpfr_dump (a);
      exit (1);
    }
  mpfr_set_prec (x, 2);
  mpfr_ui_pow_ui (x, 65537, 65535, MPFR_RNDN);
  if (mpfr_cmp_str (x, "0.11E1048562", 2, MPFR_RNDN) != 0)
    {
      printf ("Error for ui_pow_ui for 65537 ^65535 with 2 bits of precision\n");
      mpfr_dump (x);
      exit (1);
    }
  mpfr_clear (x);
  mpfr_clear (y);
  mpfr_clear (z);
  mpfr_clear (a);
}

static void
check1 (mpfr_ptr x, mpfr_prec_t prec, unsigned long nt, mpfr_rnd_t rnd)
{
  mpfr_t y, z, t;
  int inexact, compare, compare2;
  mpfr_prec_t yprec;
  mpfr_exp_t err;

  yprec = prec + 10;

  mpfr_init (y);
  mpfr_init (z);
  mpfr_init (t);
  mpfr_set_prec (y, yprec);
  mpfr_set_prec (z, prec);
  mpfr_set_prec (t, prec);

  compare = mpfr_ui_pow (y, nt, x, rnd);
  err = (rnd == MPFR_RNDN) ? yprec + 1 : yprec;
  if (mpfr_can_round (y, err, rnd, rnd, prec))
    {
      mpfr_set (t, y, rnd);
      inexact = mpfr_ui_pow (z, nt, x, rnd);
      if (mpfr_cmp (t, z))
        {
          printf ("results differ for x=");
          mpfr_out_str (stdout, 2, prec, x, MPFR_RNDN);
          printf (" n=%lu", nt);
          printf (" prec=%u rnd_mode=%s\n", (unsigned) prec,
                  mpfr_print_rnd_mode (rnd));
          printf ("got      ");
          mpfr_out_str (stdout, 2, prec, z, MPFR_RNDN);
          puts ("");
          printf ("expected ");
          mpfr_out_str (stdout, 2, prec, t, MPFR_RNDN);
          puts ("");
          printf ("approx  ");
          mpfr_print_binary (y);
          puts ("");
          exit (1);
        }
      compare2 = mpfr_cmp (t, y);
      /* if rounding to nearest, cannot know the sign of t - f(x)
         because of composed rounding: y = o(f(x)) and t = o(y) */
      if ((rnd != MPFR_RNDN) && (compare * compare2 >= 0))
        compare = compare + compare2;
      else
        compare = inexact; /* cannot determine sign(t-f(x)) */
      if (((inexact == 0) && (compare != 0)) ||
          ((inexact > 0) && (compare <= 0)) ||
          ((inexact < 0) && (compare >= 0)))
        {
          printf ("Wrong inexact flag for rnd=%s: expected %d, got %d\n",
                  mpfr_print_rnd_mode (rnd), compare, inexact);
          printf ("x="); mpfr_print_binary (x); puts ("");
          printf ("y="); mpfr_print_binary (y); puts ("");
          printf ("t="); mpfr_print_binary (t); puts ("");
          exit (1);
        }
    }

  mpfr_clear (y);
  mpfr_clear (z);
  mpfr_clear (t);
}

int
main (int argc, char *argv[])
{
  mpfr_t x, y;
  unsigned long int n;

  tests_start_mpfr ();

  mpfr_init (x);
  mpfr_init (y);

  n = randlimb ();

  MPFR_SET_INF(x);
  mpfr_ui_pow (y, n, x, MPFR_RNDN);
  if(!MPFR_IS_INF(y))
    {
      printf ("evaluation of function in INF does not return INF\n");
      exit (1);
    }

  MPFR_CHANGE_SIGN(x);
  mpfr_ui_pow (y, n, x, MPFR_RNDN);
  if(!MPFR_IS_ZERO(y))
    {
      printf ("evaluation of function in -INF does not return 0");
      exit (1);
    }

  MPFR_SET_NAN(x);
  mpfr_ui_pow (y, n, x, MPFR_RNDN);
  if(!MPFR_IS_NAN(y))
    {
      printf ("evaluation of function in NAN does not return NAN");
      exit (1);
    }

  test1 ();

  {
  mpfr_t z, t;
  mpfr_prec_t prec;
  mpfr_rnd_t rnd;
  unsigned int n;

  mpfr_prec_t p0=2, p1=100;
  unsigned int N=20;

  mpfr_init2 (z, 38);
  mpfr_init2 (t, 6);

  /* check exact power */
  mpfr_set_str_binary (t, "0.110000E5");
  mpfr_ui_pow (z, 3, t, MPFR_RNDN);

  mpfr_set_prec (x, 2);
  mpfr_set_prec (y, 2);
  mpfr_set_str (x, "-0.5", 10, MPFR_RNDZ);
  mpfr_ui_pow (y, 4, x, MPFR_RNDD);
  if (mpfr_cmp_ui_2exp(y, 1, -1))
    {
      fprintf (stderr, "Error for 4^(-0.5), prec=2, MPFR_RNDD\n");
      fprintf (stderr, "expected 0.5, got ");
      mpfr_out_str (stderr, 2, 0, y, MPFR_RNDN);
      fprintf (stderr, "\n");
      exit (1);
    }

  /* problem found by Kevin on spe175.testdrive.compaq.com
     (03 Sep 2003) */
  mpfr_set_prec (x, 2);
  mpfr_set_prec (y, 2);
  mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
  mpfr_ui_pow (y, 398441521, x, MPFR_RNDN);
  if (mpfr_cmp_ui_2exp(y, 1, 14))
    {
      fprintf (stderr, "Error for 398441521^(0.5), prec=2, MPFR_RNDN\n");
      fprintf (stderr, "expected 1.0e14, got ");
      mpfr_out_str (stderr, 2, 0, y, MPFR_RNDN);
      fprintf (stderr, "\n");
      exit (1);
    }

  mpfr_clear (z);
  mpfr_clear (t);

  mpfr_set_prec (x, 2);
  mpfr_set_str (x, "0.5", 10, MPFR_RNDN);
  check1 (x, 2, 398441521, MPFR_RNDN);  /* 398441521 = 19961^2 */

  /* generic test */
  for (prec = p0; prec <= p1; prec++)
    {
      mpfr_set_prec (x, prec);
      for (n=0; n<N; n++)
        {
          int nt;
          nt = randlimb () & INT_MAX;
          mpfr_urandomb (x, RANDS);
          rnd = RND_RAND ();
          check1 (x, prec, nt, rnd);
        }
    }
  }

  mpfr_clear (x);
  mpfr_clear (y);

  tests_end_mpfr ();
  return 0;
}